1. Field of the Invention
This invention relates to a radio communication apparatus such as a radio communication transceiver of the multi channel access (MCA) type.
2. Description of the Prior Art
Some communication stations use conventional MCA-type radio communication transceivers which automatically find an open or unoccupied channel from a plurality of channels and which perform communication via the open channel. In cases where such a MCA-type transceiver of a station is required to transmit an information signal, a transmitter side of the transceiver scans channels to find an open channel. When the open channel is found, the transmitter side transmits the information signal via the open channel. In cases where the station is in a stand-by mode, a receiver side of the transceiver scans the channels to detect a related identification (ID) signal.
During the stand-by channel scan, the receiver side checks whether or not a channel is occupied by a signal having an electric field stronger than a given level. When the channel is unoccupied, the scanning process advances to a subsequent channel and the receiver side performs a similar check with respect to the subsequent channel. Such checks are reiterated sequentially for respective channels until an occupied channel is found. In the case where an occupied channel is found, the receiver side determines whether or not a related ID signal is present in the received signal. When the related ID signal is present, the associated transmitter side is activated to transmit an answer signal via the channel. When the related ID signal is absent, the scanning process advances to a subsequent channel and the receiver side performs the previously-mentioned check with respect to the subsequent channel.
In cases where the number of the channels is large, such a conventional stand-by channel scan tends to take a considerable length of time to find a related identification signal.